New User Scanner Tuning

[Discoordination]

Hi there Laserists,

Big Will fe the Scottish Borders here! First Post on the forum. Have far too many questions but i'll stick to one area for now i think! So I have a Laserworld CS-1500 RGB. I know i read the posts about Laserworld being rubbish but i got it for £650 on ebay so prob. worth it. Now from my measurements of the scanner angle and investigation of the specs (Scanning system: Galvo system, 30.000 PPS at 4°) i should get a good ILDA test pattern with a 29cm high image at 3.1metres... ?? I only get a good pattern when i turn it down to about 4000pps regardless of whether the angle is 4 degrees or 24 degrees... Do you think this could be improved if i re-calibrate the scanners using the 6 pots on the scanner control board? I've pretty much decided that i'm going to invest in some good galvos for this laser as the performance of these seems pretty awful. However Rob seems to have nipped off on holiday for 2 weeks and i ve got another chance to get the laser out before any changes to the hardware configuration can be made. Think i found an article on scanner tuning somewhere but any links or tips would be awesome!
respect to the laser crew,

wil

[Discoordination]

Correction 10 trimmer pots labelled PR1-5 for each scanner.....

[absolom7691]

It sounds like your tuning is off. Even 12KPPS scanners look "ok" running at 15K @ 6°~8° and although LaserWolrd exaggerates their laser power (a lot) they use decent galvos and I can't see them using something less than 12KPPS. I think your angle at 3.1m should be about 21~23cm at 4° but, close enough!

The first thing you will need to do is try to find out what the pots on the driver amps do. I am not familiar with the galvos LW uses, perhaps someone else can chime in. Once you figure out Gain, Offset, Servo, LF Damping and HF Damping, you can begin to tune your galvos. Be warned, you need to have patience as it can take some time and can be frustrating. Take a look at Buffo's tuning tutorial:
http://www.photonlexicon.com/forums/...-your-scanners

He breaks it down pretty well and using this guide, I have gotten much better at tuning galvos. Good luck!

[Discoordination]

Thanks Absolom,
I've worked out what several of them do so far. I ll go back through and see if you can help me with the ones i haven't identified. 8 degrees is 4 degrees up and 4 degrees down from the centre point?
cheers,
w

[Discoordination]

And i m scanning the test pattern using Phoenix hardware check so I should set it up for 8 degrees scan angle and 15000pps to start calibrating?

[Discoordination]

Ok so this is what i worked out so far....
In order of position on the board just for the x-axis...

PR 5 - Not sure what this one does (Gain???)
PR 1 - X size!
PR 4 - Distorts central circle one direction.

PR 2 - Seems to distort the central circle in the opposite direction.
PR 3 - Stretches the central circle and some tails appear on the lines (Damping or blanking?)

Will read the tutorial and see if i can get a handle on these!

[absolom7691]

Whatever scan speed you want to display your graphics at is the speed the ILDA test pattern should be running at. If you want to display at 30K, then you need to tune for 30K.

PR 5 - Not sure what this one does (Gain???) <----- not sure what that is, maybe offset which moves entire image right or left on X axis (would move it up or down on Y axis)
PR 1 - X size! <----- This would be your Gain or Size
PR 4 - Distorts central circle one direction. <----- could be Servo or HFD

PR 2 - Seems to distort the central circle in the opposite direction. <------ could be Servo or HFD
PR 3 - Stretches the central circle and some tails appear on the lines (Damping or blanking?) <---- Sounds like LFD

[Discoordination]

Thanks absolum,
Just fixed it so that the green can be analog modulated but am kind of confused on the scanner calibration so haven't had a chance to test the new setup... PR5 doesn t seem to do anything visible really... not sure whether i should turn it down all the way once i ve reset the others and then slowly up.......???

I found a document from laserworld on their 50k scanners which have 7 trimmers per axis...
Size
Servo Gain
LFD
HFD
Position
Linearity
Offset (Don't Change)

I think i might be able to work out which is LFD and which is HFD from looking at the tutorial but what is the effect of servo??? Also my top horizontal lines seem completely displaced so if i don t have any luck sorting those out i ll post a pic (if possible) !
thanks again!
w

[Discoordination]

Arggg,
This is difficult... The thing seems to get more skewed the more i fiddle with it and it s getting late... At least nothing has broken completely yet!!! although some squiggles resulted from me touching the underside of the board on the metal case.... I keep feeling like i m turning the HD and LD down when i m turning them clockwise... Can that be right or have i got them back to front...?

So here is the theory so far:

PR 5 - Doesn't do anything obvious but has been fiddled with so probably not offset as i m not seeing anything move...
PR 1 - X size! <----- This would be your Gain or Size
PR 4 - Distorts central circle one direction. <----- could be Servo or HFD

PR 2 - Seems to distort the central circle in the opposite direction. <------ could be Servo or HFD PR 4 and 5 seem to have the opposite effect in terms of extending and shrinking the lines on the corner of the square
PR 3 - This one has the effect of making the top horizontal lines shrink or extend... This could be the servo gain????

The tutorial is good but hard to follow when you have 10 trimmer pots instead of 6 and you aren't sure which is which....

Agh well off to sleep before i electrocute myself... New day new vision... Here s the pics of what is there so far...

Pics:

[Discoordination]

Found this from William Benner:

"With respect to people trying to undergo their own tuning, the only things I worry about is "which way is increasing" and "which pot is which". Some companies try to keep "which pot is which" a secret... so before anyone tunes a scanner, they should find out definitively which pot controls servo gain, which pot controls damping, and which pot controls high frequency damping. That's critical for success.

I can say the same about "which way is increasing". American-manufactured scanner amps make complete sense. For example, when you go into your car, or your TV set, or your home stereo, and turn the knobl clockwise, it "increases" stuff (brightness, sound level, etc.). Many Chinese products are the opposite -- not because there was a conscious decision, but because they didn't know it mattered... Also, some scanner amps have some pots which increase as you rotate them clockwise, and other pots that decrease as you rotate them clockwise (on the same amp)."

So I think still issue with which pot is which and which is hf gain and lf gain... trying to attempt one assumption at a time and have managed to get a reasonable circle but not start going down the stairs... Will try to PM another guy who said he had the same model and was tuning it and see if he remembers anything....